Sonar fishing bobber what board and parts do I need

Projects General Guidance
1

What board and parts should I use

I want a arudino board that can be use with a fishing bobber with a sonar to detect fish and how deep the water and is what parts and board would I need to get start.

Then if possible what parts would I need so that I can have the reading send back as images to my computer

2

Underwater sonar is currently not possible to build with Arduino. You need specially designed transducers, which are expensive, and high voltage circuitry.

Consider this inexpensive fish finder unit instead. I have one, and it works well. Battery life is limited, though.